White Fungus on Bean Roots

Types

• Pythium root rot is also known as hollow stem. Occurring in either hot or cold weather, Pythium root rot spreads rapidly causing crop loss. Pythium root rot is soil-borne and lives in the soil for many years after infection. White mold affects bean leaves, stems and roots, and is usually seen at the end of the growing season, which often causes large losses in bean crops.

Symptoms

• The symptoms associated with Pythium root rot include white fungus on the stem and roots of the plant, followed by wilting and death. Young, immature plants often develop wet rot, which kills plants. White mold causes bean plants to develop lesions on stems, roots and leaves, which forms a white, cottony mold.

Control

• Controlling root rot and white mold in bean plants is accomplished with cultural controls. Rotate planting sites to reduce infections, since fungal diseases are soil-borne. Avoid allowing plants to stand in water, as excess moisture increases the risk of fungal disease. Applying fungicides to bean plants is often helpful in controlling disease.